The invention relates generally to device packaging and, more particularly to a universal low cost micro electro-mechanical (MEM) device package.
As is known, a wide variety of MEM device packaging approaches and techniques are commonly employed to package a variety of MEM devices, such as micro motors actuators and the like. These packaging approaches can be loosely grouped as either hybrid post processing or wafer scale capping. Hybrid post processing is generally more expensive and requires significant tooling. Wafer scale packaging, on the other hand, has the potential to be low cost, but is typically hindered by the need to provide at least one feed through from the sealed device to the external world. The feed through can be formed by etching from the backside of the wafer. However, etching through a thick wafer results in a long via that typically is quite large. On the other hand, a surface feed through is often difficult to form because the contact area must be exposed to permit the surface feed through to be formed.
One example of a wafer scale packaging technique that uses a surface feed through may be realized by inspection of a commercially available microwave MEM switch. In the MEM switch, a cap wafer with cavities etched into it is bonded to a device wafer. The cap wafer is removed from the regions where contacts are needed. Finally, the wafers are diced using a dicing saw. However, this process has several drawbacks, the process to remove undesired cap material adds significant time and expense to the process. Second, the process results in a very large area for the external pads. It would, therefore, be desirable to overcome the aforesaid and other disadvantages.